Conduit bending machine



Aug. 25, 1964 J. SHEEHAN CONDUI'I' BENDING MACHINE Filed June 15, 1960 IN V ENTOR.

cferemizb 5heeilaiz ZF LM ATTORNEYS United States Patent 3,145,757 CONDUIT BENDING MACHINE Jeremiah Sheehan, Brooklyn, N.Y., assignor to Simpson Electric Corp., New York, N.Y. Filed June 15, 1960, Ser. No. 36,358 7 Claims. ((11. 153-40) This invention relates to a machine useful for bending electric conduit and similar tubular devices.

In modern electrical installations it is customary to use rigid conduit for carrying electric Wires from outlet to outlet and throughout a building. Many mechanical difficulties arise, particularly in this day of reinforced concrete buildings, where the electric conduit must be laid before concrete is poured. Certain requirements on the job will dictate short radius of bend, often the radius being determined by the electrical code of the particular city where the installation is being made. In any event, the practical aspects of the job require that the conduit in making the radius of the bends, suffer no significant loss in diameter so that an appropriate number of wires can be passed through it.

In a city building, a large building such as an apartment house, an extremely large number of bends in conduit will be required and the problem of manpower to do the job immediately arises. The larger the job the more manpower, and it is quite obvious that very quickly in a given situation, manual bending of conduit becomes not only a physical impossibility but an economic one as well.

It is, accordingly, a fundamental object of this invention to provide a power machine for bending conduit accurately to a given radius of bend without loss of diameter of the conduit, and to a controlled amount of standoff from the radius, the machine being further of a type and character which can simultaneously bend a plurality of conduits to a bend of any angle, uniformly and accurately controlled.

Another object of the invention is to provide a machine particularly suited for the making of right angle bends in view of the fact that the right angle bend is practically the standard for electrical practice.

Other objects and advantages of the invention will in part be obvious and in part appear hereinafter.

The invention, accordingly, is embodied in a conduit bending machine which may be characterized as comprising a bed, a framework, a power member carried within said framework, a die for forming a bend linked to said power member, said die having a second relatively rotating portion for actively forming the bend, said second portion of the die consisting of rollers pivoted around said portion of said die, in combination with means for holding a plurality of tubes on the bed of the machine, and said power member being useful for causing relative rotation between the dies to take place, while simultaneously bending the conduit by means of the said dies, so as to produce a bend therein of the required overall radius, the die being so formed that substantially no loss of diameter of the conduit occurs in the process of bending.

The machine, therefore, is formed on the principal of providing a short linear power stroke, a floating center identified with one die, and a forming die rotatable around said center to define the full extent of the bend it is sought to make.

The details of the machine and the method of operation may be better understood by reference to the drawings, in which,

FIGURE 1 is a perspective view of the machine showing the relationship of the bed to the framework and the dies for forming the bend;

FIGURE 2 shows a side elevation of the machine, with a plurality of tubes in place in the process of being bent;

Patented Aug. 25, 1964 ice FIGURE 3 shows the relationship of the tubes to the bed of the machine and the power source upon completion of the bending;

FIGURE 4 is a detailed partial view of the machine in side elevation, from the direction opposite to that of FIGURE 1.

Referring now to FIGURE 1, 10 represents the machine generally, which consists of a pair of base supports 11 and 12 cross-braced at intervals 13, 14, 15, so as to define a base for the vertical supports 16, 17, 18, 19, 20, 21, 22, 23, which, with additional cross braces 24, and others parallel thereto define a cradle for holding the power member, dies, and rocking bed. The cradle is complete with horizontal supports 28 and 29 of the machine itself. Fundamentally, it will be seen that the frame of the machine, or cradle, consists of supporting members fixedly held together to define a pair of planes adequately cross-braced, etc., to support the bed of the machine at a reasonable working height for an operator. The cradle may, optionally, be equipped with casters.

The rotatable bed of the machine is formed of horizontal supports 31-32 and 33-34, cross-braced at 35, 36, 37, and pivoted at the end 38 in the cradle. The work supporting bed thus consists of pairs of supports crossbraced, etc., having the bend forming die 40, afiixed to the end of the bed in position such that conduit to be bent, when laid on the bed describes a tangent to the curve of the die. This relationship is shown in geometric detail in FIGURES 2 and 3. Normally, for right angle bends, the grooves in the forming die will be quadrants. The die may have as many grooves as is consistent with reasonable size of the machine. I have found that a 5 or 6 groove die is ample, because it will per mit a high rate of production yet will not require a very powerful drive or heavy framing.

Forming die 40 has grooves 41, 42, 43, 44, 45 useful for receiving a plurality of tubes for bending. It is preferable to these grooves be formed with high sides to prevent significant loss of diameter of tubes in the bend. The die is otherwise of conventional form, heavy enough to take the load applied by bending five or six tubes simultaneously.

At the center of curvature 50 of said die, a lever crank arm 61, 62, 63 is pivotally mounted, the said crank arm being U-shaped and pivotally connected to the fixed point 70. Pivoted at fixed point 70 on an axle mounted between vertical supports 20-21in bearings 71 and 72 is idler 73, having a set of grooves matching those in the forming die 40.

Hydraulic cylinder is pivotally mounted at 81 near the base of the machine, on cross-brace 84 carried between supports. Power applied hydraulically is most convenient for operation and it is supplied to the cylinder from the pump 82 through control valve 83 which is equipped with reversing mechanism. The cylinder, lines and valve are of conventional construction and are shown merely for completeness in showing the system for applying power.

Hydraulic cylinder 80, internally drives a piston, which moves arm 85 in a single long linear stroke. Arm 85 is pivotally connected at 86 to crank 87, which in turn is connected to crank 88, pivoted around 89, a fixed point on the rotatable bed of the machine. At the other end of crank 88, keeper or cross arm 90 is mounted to reach across the bed of the machine. Control of the amount of standolf from a bend is achieved with end stop 100, supported by arms 101 and 102, adjustably on members 103, and 104, at a level aligned with the starting position of the machine.

Referring now to the figures in succession, a typical cycle of operation commences with the machine in the empty position as shown in FIGURE 1. Conduits are laid a on the bed of the machine in the individual grooves of the die blank and placed so that their ends contact end stop 100, which fixes the amount of the standoif of the tube from the bend, as shown in FIGURE 2.

In FIGURE 3, the machine is shown after power has been applied to the hydraulic cylinder and the piston has been extended moving forming die 40 upward, and at the same time pushing conduit against rollers 73, and rotating keeper 90 into position to hold the plurality of tubes in the same relative position for uniform bending.

In FIGURE 3, the cylinder is shown at the end of the stroke with the piston fully extended for a right angle bend, the die 40 at its maximum point of travel and crank arm 61 6263 at its maximum point of travel. Following the establishment of this point, the operator relieves the pressure of fluid in the hydraulic cylinder to release the conduits with the return of the parts to the position shown in FIGURE 1, whereupon the bent conduits are merely pushed to one side off the bed of the machine, and onto a carrier or other catcher apparatus, following which the next group is loaded. The open U- shape of crank arm 6162-63 passes the ends of the bent tubes without lifting them out of the machine.

What is claimed is:

1. A machine for bending conduit in a predetermined arcuate form which comprises a base, a tilting work table pivotally supported at one end thereof on said base, a forming die rigidly supported on said tilting table at the other end thereof, a pivot point on said table at a point removed from said forming die, a link pivotally mounted at said pivot point and having an extension thereof extending over the upper surface of said table, a rolling die fixedly mounted on said base in operative alignment with said forming die, power means on said machine suitable for supplying a single linear stroke, said power means being operatively connected with said link for pivoting said link and for tilting said table, and linkage pivotally connecting said forming die to said rolling die in fixed spaced relation thereto, whereby with the placing of conduit on said table with the portion to be bent disposed between said forming die and said rolling die and upon operation of said power means to provide the application of a power stroke to said link, said link is pivoted to contact and hold said conduit on said table and said forming die is moved in the direction of said power stroke, while said table is tilted to bend said conduit between said dies.

2. A machine for bending electric conduit comprising a base, vertical and horizontal supports rigidly mounted on said base to define a cradle, a tiltable bed mounted on said cradle, one end of said bed being pivoted on said cradle, a quadrant shaped forming die rigidly secured to the other end of said bed, a roller forming die mounted on said cradle in alignment with said quadrant forming die for cooperation therewith and pivoted at a point in fixed relation to said base, linkage pivotally connecting said roller forming die and said quadrant forming die, a pivot point on said tilting bed spaced from said quadrant forming die, a power link pivoted at a midpoint at said pivot point, lateral extensions at either end of said power link, one of said extensions disposed below and one disposed above said tilting bed, and power means operable to deliver a linear power stroke connected to said lateral extension disposed below said bed, whereby with the placing of conduit on said bed with the portion to be bent disposed between said forming die and said rolling die and upon operation of said power means to deliver a linear power stroke to said power link, said power link is pivoted and said lateral extension disposed above said bed is brought down into contact with said conduit on said bed, said bed is tilted upward, and the conduit on said bed is bent around said quadrant forming die as it moves in fixed spaced relation with said roller forming die.

3. A machine for bending conduit characterized by its utilization of a plurality of pivot points for application of dynamic bending force to conduit maintained in spec ified relationship to certain fixed points, which comprises a frame of generally rectangular form suitable for sup-- porting a working bed at a useful work height to receive conduit to be bent, said work supporting bed being pivoted at one end thereof in said frame, a forming die forming a bending point at the other end of said bed fixedly mounted thereon, an intermediate pivot point aflixed to said bed, serving as a bearing, a lever pivotally mounted approximately at its midpoint on said bearing, said lever having a first end extending to a level below said work bed, and a second end extending to a level above said work bed, said second end of said lever carrying a crossarm for contacting conduits and holding them in fixed position on the work bed, the first end of said lever being pivoted to a crank which serves as a point for the application of a linear power stroke for bending conduit, a roller die fixedly mounted on said frame in operative alignment with said forming die for coaction therewith, a pair of links pivotally connecting said forming die and said rolling die and supporting said forming die and said other end of said bed for movement about said roller die when said bed is tilted, at least one of said links being of U-shaped configuration, and power means connected to said crank operable to deliver a power stroke thereto, whereby with the placement of conduit on the work bed of such machine with the portion to be bent disposed between said forming die and said rolling die and the operation of said power means for the application of a required power stroke to said crank, said lever is pivoted on said bearing bringing said cross-arm into contact with said conduit and the work bed is tilted upward in a fixed defined path forcing the conduit against the said roller die to form in said conduit a bend of the desired degree of curvature.

4. The apparatus in accordance with claim 3 wherein a measuring means is mounted on said frame in alignment with the end of the conduit to be bent prior to the operation of said power means to regulate the degree of standoff in said bends.

5. A machine in accordance with claim 3 wherein the linear stroke is provided by a hydraulic cylinder pivoted at the lower end thereof to the said lower arm.

6. In a device in accordance with claim 3, in whichsaid frame comprises a first generally rectangular section:

integrally joined to a second section spaced therefrom,- said tilting bed being pivotally attached to said first sec-- tion at the end thereof remote from said second section, said rolling die being mounted on said second section, said sections being arranged to permit free removal of bent conduit from the work bed by sliding said conduit laterally off the said work bed with the bent portion in depending relationship with said horizontal work bed.

7. In a device in accordance with claim 3, a frame consisting essentially of horizontal and vertical supports integrally joined in fixed spaced relationship to each other, said support defining a generally rectangular support, a tilting work bed thereon pivoted at one end of said frame, said frame having a second adjacent framework thereon for permitting delivery of bent conduit from said machine.

References Cited in the file of this patent UNITED STATES PATENTS 224,526 Gage, et a1. Feb. 17, 1880 1,125,241 Wilson Jan. 19, 1915 1,761,798 Potter June 3, 1930 2,208,061 Warger July 16, 1940 2,231,306 Wagenbach Feb. 11, 1941 2,430,899 Wallace Nov. 18, 1947 2,880,780 Mackey Apr. 17, 1959. 

1. A MACHINE FOR BENDING CONDUIT IN A PREDETERMINED ARCUATE FORM WHICH COMPRISES A BASE, A TILTING WORK TABLE PIVOTALLY SUPPORTED AT ONE END THEREOF ON SAID BASE, A FORMING DIE RIGIDLY SUPPORTED ON SAID TILTING TABLE AT THE OTHER END THEREOF, A PIVOT POINT ON SAID TABLE AT A POINT REMOVED FROM SAID FORMING DIE, A LINK PIVOTALLY MOUNTED AT SAID PIVOT POINT AND HAVING AN EXTENSION THEREOF EXTENDING OVER THE UPPER SURFACE OF SAID TABLE, A ROLLING DIE FIXEDLY MOUNTED ON SAID BASE IN OPERATIVE ALIGNMENT WITH SAID FORMING DIE, POWER MEANS ON SAID MACHINE SUITABLE FOR SUPPLYING A SINGLE LINEAR STROKE, SAID POWER MEANS BEING OPERATIVELY CONNECTED WITH SAID LINK FOR PIVOTING SAID LINK AND FOR TILTING SAID TABLE, AND LINKAGE PIVOTALLY CONNECTING SAID FORMING DIE TO SAID ROLLING DIE IN FIXED SPACED RELATION THERETO, WHEREBY WITH THE PLACING OF CONDUIT ON SAID TABLE WITH THE PORTION TO BE BENT DISPOSED BETWEEN SAID FORMING DIE AND SAID ROLLING DIE AND UPON OPERATION OF SAID POWER MEANS TO PROVIDE THE APPLICATION OF A POWER STROKE TO SAID LINK, SAID LINK IS PIVOTED TO CONTACT AND HOLD SAID CONDUIT ON SAID TABLE AND SAID FORMING DIE IS MOVED IN THE DIRECTION OF SAID POWER STROKE, WHILE SAID TABLE IS TILTED TO BEND SAID CONDUIT BETWEEN SAID DIES. 